Support graphql v16.

changelog.md

@@ -6,6 +6,8 @@
 
 - Updated Node.js support to `^12.20.0 || ^14.13.1 || >= 16.0.0`.
 - Updated dev dependencies, some of which require newer Node.js versions than previously supported.
+- Updated the [`graphql`](https://npm.im/graphql) peer dependency to `^16.0.0`.
+- Updated the `errorHandler` Koa middleware to avoid the `formatError` function deprecated in [`graphql`](https://npm.im/graphql) v16, using the new `GraphQLError.toJSON` method.
 
 ### Patch
 

package.json

@@ -35,7 +35,7 @@
     "node": "^12.20.0 || ^14.13.1 || >= 16.0.0"
   },
   "peerDependencies": {
-    "graphql": "0.13.1 - 15"
+    "graphql": "^16.0.0"
   },
   "dependencies": {
     "http-errors": "^1.8.0",
@@ -50,7 +50,7 @@
     "eslint-plugin-jsdoc": "^36.1.1",
     "eslint-plugin-node": "^11.1.0",
     "eslint-plugin-prettier": "^4.0.0",
-    "graphql": "^15.0.0",
+    "graphql": "^16.0.1",
     "jsdoc-md": "^11.0.2",
     "koa": "^2.13.4",
     "koa-bodyparser": "^4.3.0",

public/errorHandler.mjs

@@ -1,4 +1,3 @@
-import { formatError } from 'graphql';
 import createHttpError from 'http-errors';
 
 /**
@@ -45,7 +44,7 @@ export default function errorHandler() {
         // Error contains GraphQL query validation or execution errors.
 
         ctx.response.body.errors = error.graphqlErrors.map((graphqlError) => {
-          const formattedError = formatError(graphqlError);
+          const formattedError = graphqlError.toJSON();
 
           if (
             // Originally thrown in resolvers (not a GraphQL validation error).
@@ -87,7 +86,16 @@ export default function errorHandler() {
             httpError.extensions = error.extensions;
         }
 
-        ctx.response.body.errors = [formatError(httpError)];
+        const formattedError = {
+          message: httpError.message,
+          locations: httpError.locations,
+          path: httpError.path,
+        };
+
+        if (httpError.extensions)
+          formattedError.extensions = httpError.extensions;
+
+        ctx.response.body.errors = [formattedError];
         ctx.response.status = httpError.status;
       }